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    "# Implementation of Deque\n",
    "\n",
    "In this lecture we will implement our own Deque class!\n",
    "\n",
    "## Methods and Attributes\n",
    "\n",
    "* Deque() creates a new deque that is empty. It needs no parameters and returns an empty deque.\n",
    "* addFront(item) adds a new item to the front of the deque. It needs the item and returns nothing.\n",
    "* addRear(item) adds a new item to the rear of the deque. It needs the item and returns nothing.\n",
    "* removeFront() removes the front item from the deque. It needs no parameters and returns the item. The deque is modified.\n",
    "* removeRear() removes the rear item from the deque. It needs no parameters and returns the item. The deque is modified.\n",
    "* isEmpty() tests to see whether the deque is empty. It needs no parameters and returns a boolean value.\n",
    "* size() returns the number of items in the deque. It needs no parameters and returns an integer.\n",
    "\n",
    "## Deque Implementation"
   ]
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   "execution_count": 1,
   "metadata": {
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   "source": [
    "class Deque:\n",
    "    def __init__(self):\n",
    "        self.items = []\n",
    "\n",
    "    def isEmpty(self):\n",
    "        return self.items == []\n",
    "\n",
    "    def addFront(self, item):\n",
    "        self.items.append(item)\n",
    "\n",
    "    def addRear(self, item):\n",
    "        self.items.insert(0,item)\n",
    "\n",
    "    def removeFront(self):\n",
    "        return self.items.pop()\n",
    "\n",
    "    def removeRear(self):\n",
    "        return self.items.pop(0)\n",
    "\n",
    "    def size(self):\n",
    "        return len(self.items)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "d = Deque()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "d.addFront('hello')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "d.addRear('world')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "2"
      ]
     },
     "execution_count": 13,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "d.size()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello world\n"
     ]
    }
   ],
   "source": [
    "print d.removeFront() + ' ' +  d.removeRear()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {
    "collapsed": false
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   "outputs": [
    {
     "data": {
      "text/plain": [
       "0"
      ]
     },
     "execution_count": 15,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "d.size()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Good Job!"
   ]
  }
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